1. Field of the Invention
The present invention relates to a hollow panel and a method for manufacturing the same.
2. Description of the Related Art
Hitherto, a rail member for guiding a sliding door has been joined to a panel such as an automotive door panel.
Japanese Unexamined Patent Application Publication No. 2003-120116 discloses a door inner panel to which a guide rail member is fastened with bolts and nuts. In addition, Japanese Unexamined Patent Application Publication No. 2002-145116 discloses a quarter outer panel to which a rail member (center rail) is screwed.
However, when a rail member is fixed to a panel with bolts and nuts or screws, the rail member is held by the panel only at the bolted or screwed parts. Therefore, it is difficult to improve the ability of the panel to hold the rail member. In addition, when a rail member is fixed to a panel with bolts and nuts or screws, load tends to be concentrated at the bolted or screwed parts. Therefore, in order to bear the load, the panel needs to be thick-walled in the portion to which the rail member is joined. This causes an increase in the weight of the panel.